1. Field of the Invention
The present invention relates to a hand-operated tool for measuring a gap adjacent to a curved surface of a workpiece. More particularly, the present invention relates to a tool for measuring a gap between a first circular, semi-circular, or curved workpiece surface, and an opposing workpiece surface or object, which is spaced away from the first surface.
2. Description of the Background Art
Many different gauges are known for determining the size or extent of holes and/or spaces. Most of these devices relate to highly specialized fields where precise measurement is not only necessary, but is critical.
For example, feeler gauges and spark plug gap gauges are well known in the automotive field. Numerous gauges of this type are known and are commercially available.
In the jewelry industry, correct ring sizing is critical to ensure a comfortable yet secure fit. The apparatus of U.S. Pat. No. 4,964,222 provides a conically tapered tool for measuring the internal diameter of a ring, to ensure proper ring size.
In another field, a wedge-shaped measuring tool is known for measuring vertical or horizontal voids between two objects, between an object and a flat support surface such as a floor, or between different planes of the same object, as disclosed in U.S. Pat. No. 2,846,772, issued in 1958 to Strausser. The wedge-shaped tool of Strausser has flat surfaces on all sides thereof.
Another wedge-shaped measuring tool, which is similar to the Strausser tool, is disclosed in U.S. Design patent 411,808, issued in 1999 to Irwin. The device of the Irwin design patent tapers inwardly on two adjacent sides thereof as it approaches a tip portion, offering the user two possible measurements (length and width, depth and height, etc.) of a space between two objects, or between different planes of the same object. The wedge-shaped tool of Irwin also has flat surfaces on all sides thereof.
While the known devices provide some useful tools, and these tools are usable for their respective purposes, difficulty still occurs when attempting to accurately measure a gap between a curved workpiece surface and another workpiece feature or element, which is spaced a fixed distance away from that surface. Currently, measuring this distance is performed with cumbersome calipers and/or pin gauges, that may shift while the user attempts to adjust the tool to fit the spacing. As a result, accurate measurements, of spaces having the described curved geometry, are difficult and time-consuming to ascertain with the known measuring tools.
In particular, in the process of manufacturing spin-on cartridge type fluid filters, such as oil filters and the like, such filters include a base plate. Certain reinforcement bosses are formed on the filter base plate, for retaining and supportively reinforcing an annular seal anchored to the base plate. As a matter of quality control, during the manufacturing process, a distance or gap must be measured, between the tip of each reinforcement boss and an opposed inward-facing surface of a groove formed in the filter base plate. If this distance is not equal around the filter, within specified tolerances, the filter must be scrapped. Previous efforts to measure this boss to groove sidewall clearance gap have proven to be time-consuming and labor intensive.
As a result of the above-described difficulties, a need still exists in the art for a tool that will accurately measure a fixed distance, between a first, curved surface of a workpiece, and an opposing surface, feature, or element of the workpiece. In particular, a need exists for a tool of the described type, which is capable of measuring a variety of gaps, having dimensions falling within a specified range.
The present invention has been developed to overcome the foregoing limitations and disadvantages of conventional gap measuring tools and equipment, as used for measuring openings or gaps next to curved surfaces.
The present invention provides a tool for measuring a gap adjacent to a curved surface, including a tool body formed essentially as a curved wedge, and having a variable calibrated width along the length thereof, which decreases from a first width, at a first end thereof, to a second width thinner than the first width.
A tool according to the invention is made from a unitary piece of material in the shape of a curved wedge with calibrated ruler-like measurements etched into, or otherwise marked on the surface thereof. The curved wedge shape allows a user to easily measure multiple gap sizes with a single tool. The curved shape of the wedge allows it to fit slidably into the gap, for efficient and accurate measurement, rather than requiring a more cumbersome operation such as adjusting a caliper, or manipulating a pin gauge. In addition, the tool according to the present invention facilitates increased production speed and efficiency, by eliminating the previously required time-consuming process of re-calibrating measuring tools.
A tool, according to a first embodiment of the invention, includes a curved tool body having a substantially C-shaped cross-section. The tool body may be solid or hollow. The tool body has substantially flattened top and bottom surfaces, which may be substantially parallel to one another. The tool body has a relatively wide first end, and a second end which is narrower than the first end. The tool body tapers gradually and continuously from the first end to the second end, and becomes progressively narrower as it moves away from the first end. The tool body also gradually curves, as it moves from the first end to the second end, so that it is substantially C-shaped, as noted. The tool body has markings thereon, to indicate the thickness thereof, at selected, regularly spaced apart intervals.
For a more complete understanding of the present invention, the reader is referred to the following detailed description section, which should be read in conjunction with the accompanying drawings. Throughout the following detailed description and in the drawings, like numbers refer to like parts.